METHOD OF GROWING PURE Ge THIN FILM WITH LOW THREADING DISLOCATION DENSITY

Abstract

Provided is a method of growing a pure germanium (Ge) thin film with low threading dislocation density using reduced pressure chemical vapor deposition (RPCVD), which includes growing a Ge thin film on a silicon (Si) substrate at a low temperature, performing real-time annealing for a short period of time, and growing the annealed Ge thin film at a high temperature. The grown Ge single crystal thin film can overcome conventional problems of generation of a Si—Ge layer due to Si diffusion, and propagation of misfit dislocation to a high-temperature Ge thin film.

Description

CROSS-REFERENCE TO RELATED APPLICATION[0001]This application claims priority to and the benefit of Korean Patent Application No. 10-2008-0123326, filed Dec. 5, 2008, the disclosure of which is incorporated herein by reference in its entirety.BACKGROUND[0002]1. Field of the Invention[0003]The present invention relates to a pure germanium (Ge) single crystal layer, which is grown on a silicon substrate, and more particularly, to a method of forming a stress relaxed Ge single crystal thin film, low threading dislocation density and good surface roughness using reduced pressure chemical vapor deposition (RPCVD).[0004]2. Discussion of Related Art[0005]Development of novel devices using heterojunctions of silicon (Si) and silicon-germanium (Si—Ge) or germanium (Ge) has been conducted for several decades. These devices generally utilize a difference in band-gap energy between Si and Ge, or high-mobility characteristics generated due to stress applied according to a difference of lattice co...

AI Technical Summary

Benefits of technology

The present invention provides a method for growing pure germanium (Ge) single crystals with low threading dislocation density and smooth surface on a silicon substrate using reduced pressure chemical vapor deposition (RPCVD). The method involves growing a Ge thin film on a Si substrate at a low temperature, performing real-time annealing for a short period of time, and growing the annealed Ge thin film at a high temperature. The resulting Ge single crystals have low threading dislocation density and smooth surface. The method can be used to grow Si—Ge thin films with low threading dislocation density, and the Ge content in the Si—Ge thin film can be controlled by a ratio of source gases.

Problems solved by technology

The threading dislocation propagated to the surface may cause defects of a thin film to be formed thereon, deteriorating device's characteristics or causing leakage current.

However, since this method requires high-priced UHVCVD equipment, and annealing cannot be performed in UHVCVD, rapid thermal processing (RTP) should be added, which is a time-consuming process taking almost 4 hours.

Further, due to interdiffusion between Si and Ge caused by high-temperature annealing, a Si—Ge layer is formed at an interface, affecting a change in band-gap and the device's characteristics.

The misfit dislocation may be a cause of deterioration of the device's characteristics during the fabrication of the device.

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